Method and device for performing configured grant-based small data transmission

Abstract

A method for a UE for performing a CG-SDT is provided. The method includes receiving a CG-SDT-specific RSRP threshold from a BS, the CG-SDT-specific RSRP threshold being configured to the UE for an SSB selection for the CG-SDT; in a case that one or more SSBs with RSRPs above the CG-SDT-specific RSRP threshold are available, performing the SSB selection to determine a first SSB index from one or more SSB indices of the one or more SSBs; and performing an initial transmission of the CG-SDT or a subsequent new transmission of the CG-SDT through a first UL grant corresponding to the first SSB index.

What is claimed is: 
     
       1. A method for a User Equipment (UE) for performing a Configured Grant (CG)-based Small Data Transmission (CG-SDT), the method comprising:
 receiving a CG-SDT-specific Reference Signal Received Power (RSRP) threshold from a Base Station (BS), the CG-SDT-specific RSRP threshold being configured to the UE for a Synchronization Signal Block (SSB) selection for the CG-SDT; 
 in a case that one or more SSBs with RSRPs above the CG-SDT-specific RSRP threshold are available, performing the SSB selection to determine a first SSB index from one or more SSB indices of the one or more SSBs; and 
 performing an initial transmission of the CG-SDT or a subsequent new transmission of the CG-SDT through a first Uplink (UL) grant corresponding to the first SSB index. 
 
     
     
       2. The method of  claim 1 , further comprising:
 indicating, by a higher layer of the UE, the first SSB index to a lower layer of the UE after determining the first SSB index. 
 
     
     
       3. The method of  claim 1 , further comprising:
 determining, during the SSB selection, a second SSB index for a retransmission of the initial transmission, the second SSB index having a same value as the first SSB index. 
 
     
     
       4. The method of  claim 3 , further comprising:
 indicating, by a higher layer of the UE, the second SSB index to a lower layer of the UE after determining the second SSB index. 
 
     
     
       5. The method of  claim 1 , wherein performing the SSB selection comprises performing the SSB selection after determining that a configuration for the CG-SDT is configured. 
     
     
       6. The method of  claim 1 , wherein performing the SSB selection comprises performing the SSB selection after determining that a Timing Advance (TA) for the CG-SDT is valid. 
     
     
       7. The method of  claim 1 , wherein the one or more SSBs are configured for the CG-SDT. 
     
     
       8. The method of  claim 1 , wherein the CG-specific RSRP threshold is configured through a Small Data Transmission (SDT)-specific CG configuration. 
     
     
       9. The method of  claim 8 , wherein the SDT-specific CG configuration is configured through a Small Data Transmission (SDT) configuration. 
     
     
       10. The method of  claim 9 , wherein the SDT configuration is configured through a Radio Resource Control (RRC) release message. 
     
     
       11. A User Equipment (UE) for performing a Configured Grant (CG)-based Small Data Transmission (CG-SDT), the UE comprising:
 transmission and reception circuitry; and 
 at least one processor coupled to the transmission and reception circuitry and configured to:
 receive, by the transmission and reception circuitry, a CG-SDT-specific Reference Signal Received Power (RSRP) threshold from a Base Station (BS), the CG-SDT-specific RSRP threshold being configured to the UE for a Synchronization Signal Block (SSB) selection for the CG-SDT; 
 in a case that one or more SSBs with RSRPs above the CG-SDT-specific RSRP threshold are available, perform the SSB selection to determine a first SSB index from one or more SSB indices of the one or more SSBs; and 
 perform an initial transmission of the CG-SDT or a subsequent new transmission of the CG-SDT through a first Uplink (UL) grant corresponding to the first SSB index. 
 
 
     
     
       12. The UE of  claim 11 , wherein the at least one processor is further configured to:
 indicate, by a higher layer of the UE, the first SSB index to a lower layer of the UE after the UE determines the first SSB index. 
 
     
     
       13. The UE of  claim 11 , wherein the at least one processor is further configured to:
 determine, during the SSB selection, a second SSB index for a retransmission of the initial transmission, the second SSB index having a same value as the first SSB index. 
 
     
     
       14. The UE of  claim 13 , wherein the at least one processor is further configured to:
 indicate, by a higher layer of the UE, the second SSB index to a lower layer of the UE after determining the second SSB index. 
 
     
     
       15. The UE of  claim 11 , wherein performing the SSB selection comprises performing the SSB selection after determining that a configuration for the CG-SDT is configured. 
     
     
       16. The UE of  claim 11 , wherein performing the SSB selection comprises performing the SSB selection after determining that a Timing Advance (TA) for the CG-SDT is valid. 
     
     
       17. The UE of  claim 11 , wherein the one or more SSBs are configured for the CG-SDT. 
     
     
       18. The UE of  claim 11 , wherein the CG-specific RSRP threshold is configured through a Small Data Transmission (SDT)-specific CG configuration. 
     
     
       19. The UE of  claim 18 , wherein the SDT-specific CG configuration is configured through a Small Data Transmission (SDT) configuration. 
     
     
       20. The UE of  claim 19 , wherein the SDT configuration is configured through a Radio Resource Control (RRC) release message.